U.S. Pat. No. 4,746,682 to J. Green relates to a polyurethane flame retardant containing a polybrominated diphenyl oxide and an alkylated triaryl phosphate ester.
Certain disclosures exist in the prior art in regard to organic diphosphates of the general class ##STR1## where R can be substituted or unsubstituted alkylene, arylene, alkylene arylene, or other divalent connecting radical (e.g., diphenylene sulfone --SO--, --S--, --SO.sub.2 --), and the like and R.sup.1 can be substituted or unsubstituted aryl or alkyl. Examples of some disclosures include the following: U.S. Pat. Nos. 3,492,373; 3,869,526; and 4,203,888; British Patent No. 2,061,949; and Japanese Patent Publication Nos. 57/174,331; 71/22,584; 74/40,342; and 82/55,947. Also intended to be included within this class of compound are copending U.S. Ser. No. 374,717, filed Jul. 3, 1989, entitled "Novel Aromatic Bisphosphates" which covers compounds where R.sup.1 are aryl and R is --C.sub.6 H.sub.4 SO.sub.2 H.sub.4 -- and U.S. Ser. No. 374,716, filed Jul. 3, 1989, also entitled "Novel Aromatic Bisphosphates" which covers compounds where R.sup.1 are also aryl and R is a neopentyl group or a neopentyl group which is halogen substituted.